I need help with this problem, you don't have to tell me the answer as long as you can explain to me how to do it :)

The total cost of anja’s trip to the dentist was $628.35. she paid a flat fee of $89.95 which included the checkup and cleaning and then had 4 cavities filled, each of which cost the same amount. which shows the correct equation and value of x, the cost of each cavity filling?

Which of the following best describes the delian problem?

What is the length of side s of the square shown below?